[aldanor]

You may lose LSP state like rust-analyzer's which takes a while to restore. You may lose opened buffers and positions within them (unless you have some session restore logic which may also take time), window layout, copy buffers, edit history and lots of other state.

[carb]

Ah I don't run any LSPs so that's fair.

Retaining positions, buffers, and edit history between sessions is all straightforward in vanilla vim though. Unless you run an autolinter or formatter that edits your target file and wipes the history.

[Arch-TK]

For that there is ra-multiplex (to which I contributed sockets support).

I don't use any other LSPs which have a long warmup time, but if I did then they can also be used behind ra-multiplex.